A centrifugal compressor according to an exemplary aspect of the present disclosure includes, among other things, an impeller provided in a main flow path and configured to pressurize a main flow of fluid. The compressor also includes a secondary flow path configured to provide a secondary flow by recirculating a portion of the main flow. The amount of the main flow that becomes the secondary flow is less than or equal to 15%. A method is also disclosed.

A centrifugal compressor includes a housing providing in inlet, an impeller, a diffuser and a volute or collector. An electric motor is provided in the housing and is configured to drive at least one impeller via a shaft about an axis. The impeller includes an outlet end aligned with a diffuser and arranged at the throat. A variable fluid injector device is arranged downstream from the outlet end of the impeller in one example. The variable fluid injector device is configured to introduce high pressure fluid downstream from the impeller in response to a compressor regulation command. The injected fluid energizes the low momentum boundary layer, which provides compressor stability. A compressor controller is in communication with the variable fluid injection device to obtain a desired compressor operating condition.

This disclosure relates to a centrifugal compressor. In a first example, the compressor includes a first impeller provided in a main refrigerant flow path, a second impeller provided in the main refrigerant flow path downstream of the first impeller, and a recirculation flow path. In the first example, the recirculation flow path is provided between a first location and a second location along the main refrigerant flow path. The first location is downstream of the second location, and the second location is downstream of the first impeller. In a second example, the compressor includes an impeller provided in a main refrigerant flow path, and a recirculation flow path provided between a first location and a second location along the main refrigerant flow path. In the second example, the recirculation flow path includes a recirculation volute. Further disclosed is a method for operating a centrifugal compressor.

A scroll compressor including a compression mechanism assembled with a valve assembly disposed in a housing. The compression mechanism including a fixed scroll and an orbit scroll. The fixed scroll includes a recessed pocket having a first indentation with a first injection port and a second indentation with a second injection port. A double reed structure of the valve assembly is disposed in the recessed pocket of the fixed scroll. The double reed structure includes a first reed configured to selectively permit a flow of a fluid through the first injection port and a second reed configured to selectively permit a flow of a fluid through the second injection port. The valve assembly further includes a valve member disposed adjacent the reed structure and a valve gasket disposed between the valve member and a portion of the housing.

A compressor includes a rotor platform; a rotor blade; and a casing having an inner surface surrounding the tip and spaced radially outwardly from the tip to define a gap. A secondary air flow system includes a bleed inlet configured to remove secondary air flow from the primary air flow; an injection opening disposed in the inner surface of the casing upstream of the bleed inlet; an accessory conduit; and a plenum fluidly coupled to the bleed inlet, the injection opening, and the accessory conduit. The bleed inlet and plenum at least partially define a secondary air flow path such that a first portion of the secondary air flow is directed in through the bleed inlet, through the plenum, and out through the injection opening and a second portion of the secondary air flow is directed in through the bleed inlet, through the plenum, and out through the accessory conduit.

To solve the problems of compressor wheel blade flow separation causing surge type noises when a compressor return or recirculation valve is opened or closed, recirculation airflow from a compressor recirculation valve is fed into an annular volume, defined between inner and outer walls or shaped as a radially expanded, axially flattened cylindrical space in the compressor inlet, so that the generally unidirectional radial flow from the compressor recirculation valve is re-directed and organized as it is turned from generally radial to generally axial, merging with the general inlet flow and presenting the compressor wheel with airflow ofcircumferentially uniform flow velocity.

A centrifugal compressor for a chiller includes a casing, an inlet guide vane, an impeller downstream of the inlet guide vane, a motor and a diffuser. The casing has inlet and outlet portions with the inlet guide vane disposed in the inlet portion. The impeller is rotatable about a rotation axis defining an axial direction. The motor rotates the impeller. The diffuser is disposed in the outlet portion downstream from the impeller with an outlet port of the outlet portion being disposed between the impeller and the diffuser. A hot gas injection passage is provided to inject hot gas refrigerant between the inlet guide vane and the impeller. A controller is programmed to control an amount of the hot gas refrigerant.

A scroll compressor including a compression mechanism assembled with a valve assembly disposed in a housing. The compression mechanism including a fixed scroll and an orbit scroll. The fixed scroll includes a recessed pocket having a first indentation with a first injection port and a second indentation with a second injection port. A double reed structure of the valve assembly is disposed in the recessed pocket of the fixed scroll. The double reed structure includes a first reed configured to selectively permit a flow of a fluid through the first injection port and a second reed configured to selectively permit a flow of a fluid through the second injection port. The valve assembly further includes a valve member disposed adjacent the reed structure and a valve gasket disposed between the valve member and a portion of the housing.

Embodiments of a compressor stage, in particular for a turbocharging system and/or a turbocompound, and a process for operating a compressor stage are provided herein. The compressor stage comprises an impeller, and a vaned diffuser arranged downstream of the impeller. The vaned diffuser is in fluid connection with an outlet of the impeller and comprises an injection device configured to inject a secondary fluid into the vaned diffuser. The injection device comprises a displaceable port at least partially arranged between an adjacent pair of vanes of the diffuser.

A compressor includes a rotor platform; a rotor blade; and a casing having an inner surface surrounding the tip and spaced radially outwardly from the tip to define a gap. A secondary air flow system includes a bleed inlet configured to remove secondary air flow from the primary air flow; an injection opening disposed in the inner surface of the casing upstream of the bleed inlet; an accessory conduit; and a plenum fluidly coupled to the bleed inlet, the injection opening, and the accessory conduit. The bleed inlet and plenum at least partially define a secondary air flow path such that a first portion of the secondary air flow is directed in through the bleed inlet, through the plenum, and out through the injection opening and a second portion of the secondary air flow is directed in through the bleed inlet, through the plenum, and out through the accessory conduit.